How Ships Survive a Hurricane at Sea

For oceangoing ships, hurricanes are a threat long before they make landfall. This is how they prepare.

Storms at sea are harrowing experiences. Towering walls of water, driven by powerful winds, slam into the ship. A major storm can batter even the largest, sturdiest vessels. And they're an unavoidable part of life on the water.

Storms are part of life at sea, however. "If a ship is in the ocean, you're going to have heavy weather," says Fred Pickhardt, chief meteorologist at Ocean Weather Services. Captains can't dodge every storm, because, as Pickhardt explained, "ships are typically on a very tight schedule. Just the fuel alone on ships can be tens of thousands of dollars a day, so a two or three day delay or deviation can cost big bucks, so they always want to minimize it."

Most modern cargo ships are designed to tough out all but the heaviest weather and stay on schedule, but hurricanes are the largest and among the most dangerous storms on the ocean, and no crew wants to find itself in the midst of one.

Getting the Weather Report

To steer clear of hurricanes, mariners need good weather information. A century ago, weather updates at sea were limited to Morse code messages, but since the 1980s, weather updates have come to printers or fax machines right on the ship's bridge. U.S. cargo ships are required to carry a Navigational Telex (NAVTEX) machine, a radio receiver that picks up medium-frequency radio signals and converts them into a text printout. Another system called Weatherfax uses higher frequency radio waves to send black-and-white images to shipboard fax machines.

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Today, captains can also receive weather maps, satellite images, and other information by email. Some vessels have more high-tech tools aboard, like onboard computer systems that help plan routes based on weather forecasts. "Anything you can get on a computer at home, you can probably get at sea through a satellite connection," Pickhardt says.

Ballast

The most dangerous ship in a hurricane is an empty one. That's because the weight of cargo helps stabilize the ship against the waves. Ballast provides a little stabilizing weight when ships sail empty, but not always enough.

"It can get kind of hairy, especially if you don't have cargo," former sea captain Max Hardberger tells Popular Mechanics. "When you have only ballast water way down in the bottom of the ship, the ship has a very wicked roll to it. I've been on ships, for example, where we would go from thirty degrees heeled over on one side, and we would whip across to thirty degrees heel on the other side in a matter of three and a half seconds, so you can imagine something like that will roll your eyeteeth out."

The rolling is hard for the crew, but the worst thing for a ship is the repeated impact of the hull slamming into the troughs between waves. Modern cargo ships are constructed of thick steel, but if the waves are large enough and their battering lasts long enough, the pounding of those impacts can still break a ship apart.

Any Port in a Storm?

Cargo ships don't always head for the nearest port when a hurricane approaches, because not all ports offer the same kind of shelter.

"If you have a choice," Hardberger says, "you obviously want to find what's known as a hurricane hole, which is going to be a port with very good holding and with high cliffs or mountains around the harbor to protect you from the winds."

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Once in port, crews anchor the ship, leaving plenty of slack in the anchor chain to prevent the motion of the waves from snapping the chain. They might also put the ship's engine in reverse to put pressure on the anchor. "Once you've done those things and you're at anchor, there's not much else you can do except just hope and pray," Hardberger says.

Being caught in the wrong port can be dangerous. "After Katrina, there was a ship I went on in Lake Charles that had hammered its side against the docks during the hurricane and sustained some pretty heavy damage to its side," he says. That kind of battering takes a toll on the dock, too, and port authorities may order ships to leave ahead of a storm. "There are some ports that are so dangerous that ships will actually go out to sea, thinking that they'll be safer riding out the hurricane at sea than they are in port," Hardberger says.

Of course, the best plan is to get out of a hurricane's way. "At a modern ship speed of 14 knots, you should be able to outrun a hurricane," he says. But, Pickhardt says, "the later you leave, the less options you have. When you cut it too close, sometimes you get in trouble."

If All Else Fails

What if a ship must face a hurricane at sea? "You would try to steer for the area of the ocean that is going to see the shallowest waves and the lowest winds," Hardberger says. The "low side" or "clean side" of the storm is usually the side counterclockwise from its leading edge.

In the teeth of the storm, a ship's survival depends on two things: sea room and steering-way. Sea room means that the ship is a safe distance from anything it might crash into, like a coastline. Cargo ships try to stay well offshore if they must face a major storm at sea. If a ship is on a "lee shore," with land close by downwind, the storm can drive the ship onto the land and wreck it.

Steering-way means that the ship is moving forward with enough power to steer rather than just getting pushed around by waves and wind. The ship must keep its bow (the front end) pointing into the waves to plow through them safely, since a massive wave striking the ship's side could roll the vessel over and sink it. Wind and waves will try to turn the vessel, and pushing against them requires forward momentum.

Winning a fight against the sea depends on having a well-maintained ship, a trained and experienced crew, and a healthy dose of good luck.

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